A metallocene complex catalyst containing a cyclopentadienyl group as a ligand has been paid much attention in recent years as a novel catalyst for olefin polymerization. Of such cyclopentadienyl group ligands, a cyclopentadienyl group-containing silicon compound and a cyclopentadienyl group-containing germanium compound have been particularly paid attention because they are able to form a chiral and stereorigid metallocene complex when they coordinate to a central metal (e.g., zirconium). Especially, a zirconocene complex having such ligand is known as an important catalyst component capable of producing an olefin polymer with a high polymerization activity, as described in European Patent Application No. 129,368.
Further, the metallocene complex having such ligand is also useful as a catalyst for a Dieis-Alder react ion or a hydrogenation reaction.
The cyclopentadienyl group-containing silicon compound (or cyclopentadienyl group-containing germanium compound) employable as a ligand of the metallocene complex is generally prepared by causing a lithium, sodium or potassium salt of cyclopentadiene derivative to react with a silicon halide compound (or a germanium halide compound), as described in "Organometallics" 3 1470 (1984) , "Chem. Berichte" 119 1750 (1986) , "J. Am. Chem. Soc." 112 9558 (1990) , Japanese Patent Laid-Open Publications No. 1285/1990, No. 21607/1991, No. 268307/1992 and No. 8308/1992, EP 0549900A1, EP 0545303A1, EP 0537686A1, EP 30647A1, EP 0574597A1 and EP 0576970A1.
In detail, in Japanese Patent Laid-Open Publication No. 221285/1990 for example, a solution of an indenyl lithium salt prepared from indene and n-butyllithium is slowly added to a dimethyldichlorosilane solution, and they are reacted with each other overnight to obtain dimethyldi(1-indenyl)silane in a 71% yield. In Japanese Patent Laid-Open Publication No. 268307/1992, dimethyldi (2-methyl-1-indenyl) silane is obtained in a 16% yield in a manner similar to the above.
In "Chem. Berichte" 119 1750 (1986) , a solution containing 1,2,3,4-tetramethylcyclopentadienyl lithium and dimethyldichlorosilane is heated for 5 days to obtain dimethylbis(2,3,4,5-tetramethylcyclopentadienyl)silane in a 65% yield.
In any of the conventional processes as described above, however, the reaction must be carried out for a long period of time and the yield is low. Especially in the case of preparing a compound having such a structure that two or more groups of large steric hindrance are bonded to silicon or germanium, the yield of the compound is further lowered.
Accordingly, the advent of a process for preparing a cyclopentadienyl group-containing silicon compound or a cyclopentadienyl group-containing germanium compound in a high yield for a short period of time will be of industrially great value, because a metallocene complex catalyst component or the like can be prepared with high productivity.